feat(filter): label endpoint names id values for client-held trees

The SSR embed (65f257f3) covers trees the server renders; one path
still fell through to the flawed fallback — applying a SAVED filter
from a cold bookshelf. That page was rendered before any filter
existed (nothing embedded), and the fallback reused the suggest facet,
whose rows are MEDIA-CONSTRAINED: "feed in [A,B,C] AND title contains
Chapter" labeled only the feeds with a matching episode (the exact
live repro from the original bug report).

- GET /api/filter/labels?field=X&ids=a,b,c resolves names straight
  from the entity tables via the shared ResolveFieldLabels core
  (extracted from FilterTreeLabels): no media join, no tree
  constraint. RLS/visibility ride the request identity — a
  zero-episode subscribed feed resolves its title (pinned; the facet
  path structurally could not), an unsubscribed feed id stays unnamed
  (pinned), non-id fields are 400 (pinned), ids cap at 100.
- Client: resolveIdLabels/resolveLabelsAsync use ONLY the endpoint;
  the quiet suggest-fetch mode is deleted (its only caller was the
  flawed fallback). The saved-filter apply flow resolves through the
  endpoint and rebuilds the chips bar when labels land — chips render
  raw ids only while the round trip is in flight, never stuck.
- 188 web tests green; Go endpoint pins + filter/episode slices green;
  contract_pins documents the endpoint and the fallback removal.

cmd/server/tests/podcast_test.go

@@ -2415,3 +2415,69 @@ func TestSmartCollectionBornReversed(t *testing.T) {
 			"static collections get no chain_order seed")
 	})
 }
+
+// ---- label endpoint: names id-kind values for client-held trees ----
+
+// TestFilterLabelsEndpoint pins GET /api/filter/labels (2026-11-01):
+// the client path that never touches a server render — applying a
+// SAVED filter from a cold bookshelf — resolves names through ENTITY
+// tables, not the media-constrained suggest facet. A zero-episode feed
+// resolves its title (the facet path structurally could not); an
+// unsubscribed feed id resolves to nothing (RLS); a non-id field is a
+// 400.
+func TestFilterLabelsEndpoint(t *testing.T) {
+	setup := setupTestServer(t)
+	regUUID := getRegularUserID(t, setup.DB)
+	regToken := setup.RegularToken
+
+	lib, _ := createPodcastsLibrary(t, setup, "test LabelsEP Podcasts")
+	marker := fmt.Sprintf("labelsep%d", time.Now().UnixNano()%100000)
+
+	feedA, err := setup.DB.CreatePodcastFeed(adminSeedCtx(t, setup), database.CreatePodcastFeedParams{
+		LibraryID: lib.ID,
+		FeedUrl:   "https://feed.invalid/" + marker + "-a.xml",
+		Title:     "LabelsEP Feed A " + marker,
+	})
+	require.NoError(t, err)
+	feedB, err := setup.DB.CreatePodcastFeed(adminSeedCtx(t, setup), database.CreatePodcastFeedParams{
+		LibraryID: lib.ID,
+		FeedUrl:   "https://feed.invalid/" + marker + "-b.xml",
+		Title:     "LabelsEP Feed B " + marker,
+	})
+	require.NoError(t, err)
+	// feedA is subscribed; feedB is NOT (RLS must hide it even by id).
+	subscribeRaw(t, setup, regUUID, feedA.ID)
+
+	feedAID := uuid.UUID(feedA.ID.Bytes).String()
+	feedBID := uuid.UUID(feedB.ID.Bytes).String()
+
+	t.Run("zero_episode_feed_resolves", func(t *testing.T) {
+		code, body := podcastAuthed(t, setup, regToken, "GET",
+			"/api/filter/labels?field=feed&ids="+feedAID, "")
+		require.Equal(t, http.StatusOK, code, "%s", string(body))
+		assert.Contains(t, string(body), `"labels"`)
+		assert.Contains(t, string(body), "LabelsEP Feed A "+marker,
+			"a subscribed feed with ZERO episodes resolves its title (no media join)")
+	})
+
+	t.Run("comma_joined_ids_resolve_together", func(t *testing.T) {
+		code, body := podcastAuthed(t, setup, regToken, "GET",
+			"/api/filter/labels?field=feed&ids="+feedAID+","+feedBID, "")
+		require.Equal(t, http.StatusOK, code)
+		assert.Contains(t, string(body), "LabelsEP Feed A "+marker)
+	})
+
+	t.Run("unsubscribed_feed_stays_unnamed", func(t *testing.T) {
+		code, body := podcastAuthed(t, setup, regToken, "GET",
+			"/api/filter/labels?field=feed&ids="+feedBID, "")
+		require.Equal(t, http.StatusOK, code)
+		assert.NotContains(t, string(body), "LabelsEP Feed B "+marker,
+			"an unsubscribed feed id is invisible to resolution (RLS)")
+	})
+
+	t.Run("non_id_field_is_400", func(t *testing.T) {
+		code, body := podcastAuthed(t, setup, regToken, "GET",
+			"/api/filter/labels?field=title&ids=whatever", "")
+		assert.Equal(t, http.StatusBadRequest, code, "%s", string(body))
+	})
+}

docs/contract_pins.md

@@ -685,3 +685,21 @@ born-reversed chain/page pins replace the former native expectations
 pin from 81e54f89 was corrected while flipping: the API envelope's
 match list is NOT chain-ordered and never was — order pins live on the
 SSR page and the reader chain.
+
+## 2026-11-01 — label endpoint replaces the suggest-facet fallback
+
+`GET /api/filter/labels?field=X&ids=a,b,c` names id-kind filter values
+from their source tables (entity rows only — no media join, no tree
+constraint; visibility/RLS ride the request identity). Non-id fields
+are a 400; ids truncate at the same 100 cap the SSR embed uses.
+
+The client's label resolution (`resolveIdLabels`/`resolveLabelsAsync`)
+now uses ONLY this endpoint. The former fallback — the quiet suggest
+fetch through the MEDIA-CONSTRAINED facet — is deleted: it labeled only
+the ids whose media matched the tree's sibling rules (the live feed
+repro), which mattered exactly where the SSR embed can't reach:
+applying a SAVED filter from a cold bookshelf. The apply flow now
+resolves through the endpoint and rebuilds the chips bar when labels
+land. Pinned (TestFilterLabelsEndpoint): a zero-episode feed resolves
+its title, comma-joined ids resolve together, an unsubscribed feed id
+stays unnamed (RLS), non-id fields are 400.

internal/handlers/media.go

@@ -248,6 +248,31 @@ func NewMediaHandler(db *database.Queries, raw database.DBTX, libraryService *se
 // resolve id labels through it — 2026-11-01).
 func (h *MediaHandler) SearchService() *services.SearchService { return h.searchService }
 
+// ResolveFilterLabels — GET /api/filter/labels?field=X&ids=a,b,c names
+// id-kind filter values straight from their source tables: the client
+// path that never touches a server render (applying a SAVED filter
+// from a cold bookshelf) would otherwise fall back to the suggest
+// facet, whose rows are media-constrained and label only the ids whose
+// media matches the tree's sibling rules (2026-11-01 feed repro).
+// Visibility/RLS ride the request identity, same as the SSR embed.
+func (h *MediaHandler) ResolveFilterLabels(c *echo.Context) error {
+	user := c.Get("user").(database.Users)
+	field := c.QueryParam("field")
+	if !services.IsIDValuedField(field) {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "field is not an id-valued filter field"})
+	}
+	ids := services.ParseUUIDValues(strings.Split(c.QueryParam("ids"), ","))
+	if len(ids) == 0 {
+		return c.JSON(http.StatusBadRequest, map[string]string{"error": "ids required"})
+	}
+	if len(ids) > services.MaxResolveIDs {
+		ids = ids[:services.MaxResolveIDs]
+	}
+	labels := h.SearchService().ResolveFieldLabels(
+		c.Request().Context(), user.ID, field, ids)
+	return c.JSON(http.StatusOK, map[string]interface{}{"labels": labels})
+}
+
 func (h *MediaHandler) ExecuteSearch(ctx context.Context, params services.SearchParams) ([]database.SearchMediaItemsUnifiedRow, int, error) {
 	return h.searchService.ExecuteSearch(ctx, params)
 }

internal/router/search.go

@@ -16,6 +16,10 @@ func registerSearchRoutes(cfg *Config) {
 	// JWT middleware for protected routes
 	jwtMiddleware := createJWTMiddleware(cfg)
 	protected := e.Group("/api", jwtMiddleware)
+	// Filter label resolution (2026-11-01): names id-kind filter values
+	// from their source tables for trees the server didn't render (the
+	// cold saved-filter apply). Visibility/RLS ride the request identity.
+	protected.GET("/filter/labels", cfg.MediaHandler.ResolveFilterLabels)
 	// Search endpoint - returns JSON or HTML based on HX-Request header
 	protected.GET("/media-items/search", func(c *echo.Context) error {
 		// Check if HTMX request (expects HTML)

internal/services/filter_labels.go

@@ -29,9 +29,25 @@ import (
 // a legal pick, the resolver only names it.
 // ════════════════════════════════════════════════════════════════════
 
-// maxResolveIDs bounds one field's resolution query (picks accumulate
+// MaxResolveIDs bounds one field's resolution query (picks accumulate
-// per rule; menus cap far below this).
+// per rule; menus cap far below this). The label endpoint truncates to
-const maxResolveIDs = 100
+// the same cap.
+const MaxResolveIDs = 100
+
+// IsIDValuedField — whether the field's values are entity ids (the
+// label endpoint's accepted universe: id-kind + a known source).
+func IsIDValuedField(field string) bool {
+	f, ok := FilterFieldByKey(field)
+	if !ok {
+		return false
+	}
+	return valueKindFor(f.Kind, field) == VKId && f.Suggest != ""
+}
+
+// ParseUUIDValues splits comma-joined picks into uuids, skipping junk.
+func ParseUUIDValues(values []string) []uuid.UUID {
+	return parseUUIDValues(values)
+}
 
 // FilterTreeLabels resolves every id-kind rule value in the tree to its
 // display name. Best-effort by design: a resolve failure degrades to
@@ -64,7 +80,7 @@ func (s *SearchService) FilterTreeLabels(ctx context.Context, userID pgtype.UUID
 				continue
 			}
 			for _, id := range parseUUIDValues(c.Values) {
-				if len(byField[c.Field]) >= maxResolveIDs {
+				if len(byField[c.Field]) >= MaxResolveIDs {
 					return
 				}
 				byField[c.Field] = append(byField[c.Field], id)
@@ -74,7 +90,22 @@ func (s *SearchService) FilterTreeLabels(ctx context.Context, userID pgtype.UUID
 	walk(tree.Children)
 
 	for field, ids := range byField {
-		f, _ := FilterFieldByKey(field)
+		for k, v := range s.ResolveFieldLabels(ctx, userID, field, ids) {
+			labels[k] = v
+		}
+	}
+	return labels
+}
+
+// ResolveFieldLabels names one field's picked ids against its source
+// table — the shared core of the SSR embed and the label endpoint.
+// Unknown fields resolve to nothing (the caller validates).
+func (s *SearchService) ResolveFieldLabels(ctx context.Context, userID pgtype.UUID, field string, ids []uuid.UUID) map[string]string {
+	labels := map[string]string{}
+	f, ok := FilterFieldByKey(field)
+	if !ok {
+		return labels
+	}
 	idArgs := make([]uuid.UUID, len(ids))
 	copy(idArgs, ids)
 	var sqlStr string
@@ -101,13 +132,14 @@ WHERE COALESCE(lv.is_visible, true) = true AND l.id = ANY($1)`
 		sqlStr = `SELECT id::text, username FROM users WHERE id = ANY($1)`
 		args = []any{idArgs}
 	default:
-			continue
+		return labels
 	}
 	rows, err := s.raw.Query(ctx, sqlStr, args...)
 	if err != nil {
 		log.Printf("[filter-labels] resolve %q failed: %v", field, err)
-			continue
+		return labels
 	}
+	defer rows.Close()
 	for rows.Next() {
 		var v, display string
 		if err := rows.Scan(&v, &display); err != nil {
@@ -115,7 +147,5 @@ WHERE COALESCE(lv.is_visible, true) = true AND l.id = ANY($1)`
 		}
 		labels[v] = display
 	}
-		rows.Close()
-	}
 	return labels
 }

web/src/bookshelf.ts

@@ -287,6 +287,15 @@ Alpine.data("bookshelf", () => ({
       // Rehydrate the rule-builder tree from the refilled form
       builderData()?.hydrateFromForm();
 
+      // Cold-cache labels (2026-11-01): this page was rendered BEFORE
+      // the filter existed, so the SSR embed has no names for the saved
+      // filter's ids — resolve through the label endpoint, then rebuild
+      // the chips (without the refresh they'd show raw ids until the
+      // next grid event).
+      void builderData()
+        ?.resolveLabelsAsync()
+        .then(() => refreshFilterChips());
+
       // Trigger HTMX to apply the filter by submitting the form
       window.htmx.trigger(filterForm, "submit");
 

web/src/filter_builder.test.ts

@@ -466,20 +466,44 @@ describe("id-kind value cells", () => {
         url = String(u);
         return {
           ok: true,
-          json: async () => ({ results: [{ value: "lib-9", display: "Ebooks", count: 4 }] }),
+          json: async () => ({ labels: { "lib-9": "Ebooks" } }),
         };
       }),
     );
     c.resolveIdLabels();
     await vi.waitFor(() => expect(c.idLabels["lib-9"]).toBe("Ebooks"));
-    // the stored id rides as the typed lookup
+    // resolution rides the LABEL ENDPOINT (entity tables, no media
-    expect(url).toContain("library=lib-9");
+    // constraints) — not the suggest facet
+    expect(url).toContain("/api/filter/labels");
+    expect(url).toContain("field=library");
+    expect(url).toContain("ids=lib-9");
     expect(c.idChipsFor([0]).map((ch) => ch.label)).toEqual(["Ebooks"]);
     // label resolution never opens a menu
     expect(c.suggestionsOpen).toBe("");
     vi.unstubAllGlobals();
   });
 
+  it("unlabeled ids from a PARTIAL response stay raw, labeled ones resolve", async () => {
+    // the server can only name what exists (invisible/unsubscribed ids
+    // return nothing) — the rest must keep their raw ids, not break
+    const c = filterBuilderData();
+    c.filterTree = {
+      mode: "all",
+      children: [{ field: "library", op: "in", values: ["lib-1,lib-404"] }],
+    };
+    vi.stubGlobal(
+      "fetch",
+      vi.fn(async () => ({
+        ok: true,
+        json: async () => ({ labels: { "lib-1": "Comics" } }),
+      })),
+    );
+    c.resolveIdLabels();
+    await vi.waitFor(() => expect(c.idLabels["lib-1"]).toBe("Comics"));
+    expect(c.idChipsFor([0]).map((ch) => ch.label)).toEqual(["Comics", "lib-404"]);
+    vi.unstubAllGlobals();
+  });
+
   it("opening the menu after a pick browses the WHOLE list (regression)", async () => {
     const c = filterBuilderData();
     c.filterTree = {

web/src/filter_builder.ts

@@ -466,7 +466,7 @@ export function filterBuilderData() {
       // the tree's id-kind values to names at render time and embedded
       // the map here — ingest it BEFORE any tree lands, so the cells
       // show names from the very first paint and resolveIdLabels (the
-      // quiet fetch below) early-returns instead of hitting the server.
+      // label endpoint below) early-returns instead of hitting it.
       const labelsRaw = el?.dataset.idLabels;
       if (labelsRaw) {
         try {
@@ -502,7 +502,7 @@ export function filterBuilderData() {
         this.hydrateFromForm();
       }
       // Anything still unlabeled (a tree hydrated from a form the SSR
-      // didn't know about) resolves through the quiet fetch fallback.
+      // didn't know about) resolves through the label endpoint.
       this.resolveIdLabels();
     },
     // treeJSON is the APPLY wire for collection mounts: the page's
@@ -725,28 +725,58 @@ export function filterBuilderData() {
       this.openMenu = "";
       this._touch();
     },
-    // resolveIdLabels — a freshly ingested tree (page load, the Apply
+    // resolveIdLabels — fire-and-forget wrapper (init/ingest paths).
-    // reload) carries id-kind values with no labels in sight; one QUIET
-    // fetch per id-kind rule fills idLabels so the cells render names,
-    // not uuids (2026-11-01: the library cell reverted to the id after
-    // Apply because labels only ever came from suggestion picks).
     resolveIdLabels(): void {
-      const visit = (node: FilterRuleState | FilterGroupState, path: number[]): void => {
+      void this.resolveLabelsAsync();
+    },
+
+    // resolveLabelsAsync — names every UNLABELED id-kind value in the
+    // tree through the label endpoint (entity tables, no media
+    // constraints). The SSR embed covers page renders; this covers
+    // trees the client holds that the server never saw — applying a
+    // SAVED filter from a cold bookshelf (2026-11-01: the old fallback
+    // reused the suggest facet, which labels only the ids whose media
+    // matches the tree's sibling rules). Resolves when labels have
+    // landed so callers can refresh id-labeled UI (the chips bar).
+    async resolveLabelsAsync(): Promise<void> {
+      const byField: Record<string, Set<string>> = {};
+      const visit = (node: FilterRuleState | FilterGroupState): void => {
         if (isRule(node)) {
-          const meta = FIELD_BY_KEY.get(node.field);
+          if (FIELD_BY_KEY.get(node.field)?.valueKind !== "id") return;
-          if (meta?.valueKind !== "id") return;
           const ids = node.values
             .join(",")
             .split(",")
             .filter((v) => v.trim() !== "");
           if (ids.length === 0) return;
-          if (ids.every((v) => this.idLabels[v] !== undefined)) return;
+          const unlabeled = ids.filter((v) => this.idLabels[v] === undefined);
-          void this.fetchSuggestions(path.join("-"), path, node, true);
+          if (unlabeled.length === 0) return;
+          const set = (byField[node.field] ??= new Set<string>());
+          unlabeled.forEach((v) => set.add(v));
           return;
         }
-        node.children.forEach((child, idx) => visit(child, [...path, idx]));
+        node.children.forEach(visit);
       };
-      this.filterTree.children.forEach((child, idx) => visit(child, [idx]));
+      this.filterTree.children.forEach(visit);
+      const fields = Object.keys(byField);
+      if (fields.length === 0) return;
+      await Promise.all(
+        fields.map(async (field) => {
+          const ids = [...byField[field]].join(",");
+          try {
+            const response = await fetch(
+              `/api/filter/labels?field=${encodeURIComponent(field)}&ids=${encodeURIComponent(ids)}`,
+              { headers: authHeaders() },
+            );
+            if (!response.ok) return;
+            const data = (await response.json()) as { labels?: Record<string, string> };
+            for (const [id, label] of Object.entries(data.labels ?? {})) {
+              this.idLabels[id] = label;
+            }
+          } catch {
+            // offline/failed: cells keep the raw ids (the pre-embed floor)
+          }
+        }),
+      );
     },
 
     // valuePlaceholderFor — the value cell's hint. Id-kind cells are
@@ -930,20 +960,13 @@ export function filterBuilderData() {
         void this.fetchSuggestions(rowKey, path, rule);
       }, 250);
     },
-    async fetchSuggestions(
+    async fetchSuggestions(rowKey: string, path: number[], rule: FilterRuleState): Promise<void> {
-      rowKey: string,
-      path: number[],
-      rule: FilterRuleState,
-      quiet = false,
-    ): Promise<void> {
       const meta = FIELD_BY_KEY.get(rule.field);
       if (!meta || !meta.suggest) return;
       // Fixed-option fields never hit the server.
       if (meta.valueKind === "fixed") return;
       const typed = (
-        this.isIdValueRow(path)
+        this.isIdValueRow(path) ? (this.idDrafts[path.join("-")] ?? "") : (rule.values[0] ?? "")
-          ? (this.idDrafts[path.join("-")] ?? (quiet ? rule.values.join(",") : ""))
-          : (rule.values[0] ?? "")
       ).trim();
       // 1 char is too little to filter on; EMPTY means BROWSE — the
       // user clicked the box to see the field's top values under the
@@ -952,12 +975,9 @@ export function filterBuilderData() {
       if (typed.length === 1) return;
       // cookie auth carries the call; a null bearer must not strand it
       // Open the menu NOW (loading state) — never a blank flash.
-      // QUIET mode (label resolution) touches no menu state.
-      if (!quiet) {
       this.suggestions[rowKey] = [];
       this.suggestionsLoading = rowKey;
       this.suggestionsOpen = rowKey;
-      }
       // The menu is computed under the suggest-constraint tree: AND
       // siblings keep narrowing, OR siblings drop (a same-field pick
       // negates in, taking its value off the list), and the edited
@@ -986,10 +1006,10 @@ export function filterBuilderData() {
         for (const s of data.results ?? []) {
           if (s.display) this.idLabels[s.value] = s.display;
         }
-        if (!quiet) this.suggestions[rowKey] = data.results ?? [];
+        this.suggestions[rowKey] = data.results ?? [];
       } catch (error) {
         console.warn("suggestion fetch failed", error);
-        if (!quiet) this.suggestions[rowKey] = [];
+        this.suggestions[rowKey] = [];
       } finally {
         if (this.suggestionsLoading === rowKey) this.suggestionsLoading = "";
       }